Monograph - Metrohm

20 Practical thermometric titrimetry
7. Types of thermometric titration
Thermometric titrimetry can be used for the following reaction types:
• Acid-base (acidimetry and alkalimetry)
• Redox
• Precipitation
• Complexometric
Because the sensor does not interact electrically or electrochemically with the solution,
electrical conductance of the titrating medium is not a prerequisite for a successful determination.
Titrations may be carried out in completely non-conducting, non-polar media
if required. Further, titrations may be carried out in turbid solutions or even suspensions
of solids. Titrations where precipitates are formed can also be carried out.
7.1. Acid-base titrations
7.1.1 Determination of fully dissociated acids and bases
The heat of neutralization of a fully dissociated acid with a fully dissociated base (see
Figure 11) is approximately –56 kJ/mol and can be calculated as a standard enthalpy of
reaction using standard enthalpies of formation.
H + + OH – H 2 O
ΔH 0 f (kJ/mol) 0 –230.0 –285.8 ΔH 0 r = –55.8 kJ/mol
Fig. 11: Titration of NaOH with
1 mol/L HCl.
The reaction is strongly exothermic and thus provides an excellent basis for a wide range
of analyses in industry. An advantage for the industrial analyst is that the use of stronger
titrants (1…2 mol/L) permits a reduction of the sample preparation effort. Samples can
often be directly and accurately dispensed into the titration vessel prior to titration.